1a. Objectives (from AD-416)
Soybean yields are affected quantitatively and qualitatively by fungi, insects, nematodes, and viruses. The ability of pathogens and pests to colonize and/or infect soybean plants is the result of interactions of pathogen and host genes that allow pathogenic organisms to reproduce and cause disease. The objective of this cooperative research project is to identify and characterize the expression of soybean and pathogen genes involved in the establishment and/or maintenance of disease-causing interactions.
1b. Approach (from AD-416)
Candidate soybean genes that support/permit pathogen accumulation or that are involved in pathogenesis will be identified through the genetic analysis of soybean lines differing in their susceptibility to pathogens and pests. In addition, genes expressed at the host-pathogen interface will be identified and characterized using genetic and expression profiling techniques. The involvement of the genes in disease will be confirmed by gene-specific complementation and/or gene silencing. Pathogen genes will be identified by similar genetic and expression profiling techniques. Host and pathogen proteins that physically interact in diseased cells will be identified through in vivo interaction studies and in vitro protein binding and affinity chromatography analyses.
3. Progress Report
To understand the mechanisms of resistance of soybean plants to infection by Tobacco streak virus (TSV), small RNAs were isolated and sequenced from healthy and TSV-infected plants. The short RNA sequences were computationally mapped to TSV genomic RNAs, soybean messenger RNAs and the soybean genome sequence. The distribution of small RNAs produced from TSV genomic RNAs was not uniform, suggesting that the nucleotide sequences of or secondary structures in TSV RNAs influenced how TSV RNAs were degraded by host defenses. TSV infection also altered the accumulation of small RNAs from a subset of soybean genes. Activities of this project are monitored through periodic meetings, phone calls and e-mails.